Drowsiness determination system and drowsiness determination method

Abstract

A drowsiness determination system includes a first acquirer, a second acquirer, a third acquirer, and a determiner. The first acquirer acquires vibration information indicating the vibration of a vehicle. The second acquirer acquires head information indicating a variation in the movement of the head of an occupant. The third acquirer acquires sitting height information indicating the sitting height of the occupant. The determiner determines whether the occupant is drowsy based on the head information and the sitting height information, when the vibration information indicates the occurrence of the vibration of the vehicle.

The invention claimed is: 
     
         1 . A drowsiness determination system comprising:
 a circuit configured to:   acquire vibration information indicating vibration of a vehicle;   acquire head information indicating a variation in movement of a head of an occupant;   acquire sitting height information indicating a sitting height of the occupant; and   determine whether the occupant is drowsy based on the head information and the sitting height information, when the vibration information indicates occurrence of the vibration of the vehicle,   wherein the circuit compares the head information and a threshold value to determine whether the occupant is drowsy, and   the circuit determines the threshold value from a plurality of threshold value candidates based on the sitting height information.   
     
     
         2 . The drowsiness determination system according to  claim 1 ,
 wherein the circuit estimates the sitting height based on an image obtained by imaging the head to acquire the sitting height information.   
     
     
         3 . The drowsiness determination system according to  claim 1 ,
 wherein the head information includes at least one of
 a delay time until the variation in the movement of the head occurs in a predetermined period after a time at which the vibration of the vehicle occurs, 
 a maximum value of an amplitude of the variation in the movement of the head relative to a predetermined position in the predetermined period, 
 an average value of the amplitude of the variation in the movement of the head relative to the predetermined position in the predetermined period, or 
 a dispersion of positions of the head relative to the predetermined position in the predetermined period. 
   
     
     
         4 . The drowsiness determination system according to  claim 3 ,
 wherein the circuit resets a measurement of the predetermined period when the predetermined period elapses or when magnitude of the vibration of the vehicle exceeds a predetermined value.   
     
     
         5 . The drowsiness determination system according to  claim 4 ,
 wherein the circuit does not determine whether the occupant is drowsy until the magnitude of the vibration of the vehicle exceeds the predetermined value after the measurement of the predetermined period is reset.   
     
     
         6 . The drowsiness determination system according to  claim 1 ,
 wherein the circuit decelerates the vehicle when the vibration of the vehicle does not occur for a predetermined time or more.   
     
     
         7 . The drowsiness determination system according to  claim 1 ,
 wherein the circuit further determines whether the occupant is drowsy based on magnitude of the vibration information.   
     
     
         8 . The drowsiness determination system according to  claim 7 ,
 wherein when the circuit determines whether the occupant is drowsy based on the magnitude of the vibration information, a range in which the vibration information is determined to be small is wider than a range in which the vibration information is determined to be large.   
     
     
         9 . The drowsiness determination system according to  claim 1 ,
 wherein the circuit further determines a representative value of an eyelid position of the occupant in a predefined period from the head information based on an image obtained by imaging the head, and determines whether the occupant is drowsy with consideration given to the representative value of the eyelid position.   
     
     
         10 . The drowsiness determination system according to  claim 9 ,
 wherein the circuit determines head drowsiness and eyelid drowsiness, and determines whether the occupant is drowsy by assigning weights to the head drowsiness and the eyelid drowsiness, the head drowsiness being determined based on the head information and the sitting height information, the eyelid drowsiness being determined based on the representative value of the eyelid position.   
     
     
         11 . The drowsiness determination system according to  claim 10 ,
 wherein the circuit determines whether the occupant is wearing eyeglasses based on the head information,   when the occupant is wearing the eyeglasses, the circuit determines a type of the eyeglasses, and   the circuit determines whether the occupant is drowsy by assigning weights to the head drowsiness and the eyelid drowsiness according to a result of determining the type of the eyeglasses.   
     
     
         12 . The drowsiness determination system according to  claim 11 ,
 wherein when the occupant is not wearing sunglasses, the circuit assigns a greater weight to the eyelid drowsiness relative to the head drowsiness, and   when the occupant is wearing the sunglasses, the circuit assigns a less weight to the eyelid drowsiness relative to the head drowsiness.   
     
     
         13 . A drowsiness determination method comprising:
 acquiring vibration information indicating vibration of a vehicle;   acquiring head information indicating a variation in movement of a head of an occupant;   acquiring sitting height information indicating a sitting height of the occupant;   determining whether the occupant is drowsy based on the head information and the sitting height information, when the vibration information indicates occurrence of the vibration of the vehicle;   comparing the head information and a threshold value to determine whether the occupant is drowsy; and   determining the threshold value from a plurality of threshold value candidates based on the sitting height information.   
     
     
         14 . The drowsiness determination method according to  claim 13 ,
 wherein whether the occupant is drowsy is determined based further on magnitude of the vibration information.   
     
     
         15 . The drowsiness determination method according to  claim 13 , further comprising
 determining a representative value of an eyelid position of the occupant in a predefined period from the head information based on an image obtained by imaging the head,   wherein whether the occupant is drowsy is determined with consideration given to the representative value of the eyelid position.   
     
     
         16 . A drowsiness determination system comprising:
 a circuit configured to:   acquire vibration information indicating vibration of a vehicle;   acquire head information indicating a variation in movement of a head of an occupant;   acquire sitting height information indicating a sitting height of the occupant; and   determine whether the occupant is drowsy based on the head information and the sitting height information, when the vibration information indicates occurrence of the vibration of the vehicle,   wherein the circuit includes a determination model into which the vibration information and the head information are input and which outputs a result of the determination of whether the occupant is drowsy, and   the circuit determines the determination model from a plurality of determination model candidates based on the sitting height information.   
     
     
         17 . A drowsiness determination system comprising:
 a circuit configured to:   acquire vibration information indicating vibration of a vehicle;   acquire head information indicating a variation in movement of a head of an occupant;   acquire sitting height information indicating a sitting height of the occupant; and   determine whether the occupant is drowsy based on the head information and the sitting height information, when the vibration information indicates occurrence of the vibration of the vehicle,   wherein the circuit further determines whether the occupant is drowsy based on magnitude of the vibration information, and   when the circuit determines whether the occupant is drowsy based on the magnitude of the vibration information, a range in which the vibration information is determined to be small is wider than a range in which the vibration information is determined to be large.   
     
     
         18 . The drowsiness determination system according to  claim 17 ,
 wherein the circuit includes a determination model into which the vibration information and the head information are input and which outputs a result of the determination of whether the occupant is drowsy, and   the circuit determines the determination model from a plurality of determination model candidates based on the sitting height information.